In Vitro antibacterial properties of aqueous extract of garlic against on common diarrhea causing bacteria

Garlic (Allium sativum) has been considered to be an excellent medical panacea and a natural antimicrobial agent that can be used as an alternative form of treatment of pathogenic infections. The aim of this study was to assess the effect of different concentrations of aqueous extract of garlic powder (AEGP) and aqueous extract of garlic tablet (AEGT) against three gram-negative diarrhea causing bacteria including Salmonella typhimurium, Shigella dysenteriae and Escherichia coli, in vitro. In this research, aqueous extracts of garlic were prepared using Bakri and Douglas method. Also Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of AEGP and AEGT were tested through Standard Tube Test. Data were analyzed by Student t Test of SPSS software. The MICs of AEGP and AEGT against on Salmonella typhimurium, Shigella dysenteriae and Escherichia coli were 12.5,12.5, 6.25 mg/ml and 40, 40, 20 mg/ml respectively. The MBCs of AEGP and AEGT on tested microorganisms were 25,25, 12.5 mg/ml and 80, 80, 40 mg/ml respectively. The results of present study showed that the inhibitory and bactericidal effects of AEGP was much more than that of AEGT (P<0.05), either on tested microorganisms in vitro. The results of our research indicated that aqueous extract of garlic (AEG) especially AEGP have significant antibacterial effects on the tested diarrhea causing microorganisms, in vitro. Further studies will be needed for pharmacological standardization and clinical evaluation of garlic aqueous extract, in vivo.